Exhibit 21 LIST OF SUBSIDIARIES -------------------- STATE OF -------- COMPANY INCORPORATION D/B/A - ------- ------------- ----- G-I Holdings Inc. Delaware G Industries Corp. Delaware GAF Building Materials Corporation Delaware Building Materials Delaware GAF Materials Corporation of America Corporation & Old American Products U.S. Intec Holdings Inc. Delaware U.S. Intec, Inc. Texas Tri-Ply Corporation Exterior Technologies Corporation Texas Intec Marine Inc. Texas USI Materials Inc. Delaware GAF Leatherback Corp. Delaware BMCA Insulation Products Inc. Delaware BMC Warehousing Inc. Delaware GAFTECH Corporation Delaware South Ponca Realty Corp. Delaware GAF Real Properties Inc. Delaware BMCA Receivables Corp. Delaware Pequannock Valley Claim Service Delaware Company, Inc. GAF Premium Products Inc. Delaware Wind Gap Real Property Acquisition Delaware Corp. GAF Fiberglass Corporation Delaware Merick Inc. Delaware GAF Broadcasting Company, Inc. Delaware GAF Properties Inc. Delaware Q 104.3 Listeners Club Inc. Delaware ACI Inc. Georgia General Aniline & Film Corporation Delaware BWater Corp. Delaware GAF Roofing Manufacturing Corp. Delaware